Buying first camper. Few simple questions...

Don't run right out and buy a generator. Most places that you will go fishing already have electric (private CG's and state parks). The exceptions are usually in the cooler mountains (such as Pisgah Forest there in NC) where A/C is not needed. For 3-5 days, if you have a couple of good batteries, you'll be fine - just mind the use of the water pump or anything else that has a motor in it - they are the quickest drains. Or you can add some solar to keep them charged - that's what we do.